cgalMeshes (version 2.2.0)

sphericalTriangle: Spherical triangle

Description

Mesh of a spherical triangle.

Usage

sphericalTriangle(A, B, C, center = c(0, 0, 0), radius = 1, iterations = 4)

Value

A cgalMesh object. The mesh has normals.

Arguments

A, B, C

the three vertices of the triangle, each given either as a pair of numbers: the polar angle (between 0 and pi) and the azimuthal angle (between 0 and 2pi), or as Cartesian coordinates

center

center of the sphere

radius

radius of the sphere, ignored if the three vertices are given as Cartesian coordinates

iterations

number of iterations used to construct the mesh of the sphere

Examples

library(cgalMeshes)
library(rgl)
# orthant
A <- c(0, pi/2)
B <- c(pi/2, pi/2)
C <- c(0, 0)
mesh <- sphericalTriangle(A, B, C)
rmesh <- mesh$getMesh()
open3d(windowRect = 50 + c(0, 0, 512, 512))
view3d(30, 30)
shade3d(rmesh, color = "red")
wire3d(rmesh)

# spherical icosahedron ####
library(cgalMeshes)
library(rgl)
icosahedron <- icosahedron3d()
vertices    <- icosahedron[["vb"]][-4L, ]
faces       <- icosahedron[["it"]]
colors <- rainbow(ncol(faces))
open3d(windowRect = 50 + c(0, 0, 512, 512))
for(i in 1L:ncol(faces)) {
  triangle <- faces[, i]
  A <- vertices[, triangle[1L]]
  B <- vertices[, triangle[2L]]
  C <- vertices[, triangle[3L]]
  mesh <- sphericalTriangle(A, B, C)
  rmesh <- mesh$getMesh()
  shade3d(rmesh, color = colors[i])
  wire3d(rmesh)
}